Non-epithelial neoplasms of the prostate

Rare melanosis in the urinary bladder and prostate: a case report

Melanosis, the aberrant deposition of melanin pigment in the absence of melanocytes, is very rare in the genitourinary tract. We report a case of a 74-year-old male with symptomatic benign prostatic hyperplasia. Diagnostic cystourethroscopy demonstrated bladder mucosa remarkable for numerous flat, velvety, and brown-black lesions. The patient underwent cystolitholapaxy, transurethral resection of the prostate, and bladder biopsy. Microscopic examination of the bladder biopsy demonstrated urothelium with granular, black pigmentation within the mucosa and histiocytes in the lamina propria; a Fontana Masson stain was positive for melanin. Microscopic examination of the transurethral resection of the prostate demonstrated nodular hyperplasia with focal, black pigmentation of the stroma. The rarity of bladder and prostate melanosis highlights the need for further investigation to elucidate its clinical significance and provide assurance of its benignity. Despite its rarity, melanosis should be kept in the differential diagnosis when melanotic lesions are encountered during cystoscopy.

Malignant melanoma of the prostate: Primary or metastasis? A case report

BACKGROUND

Malignant melanoma of the prostate is rare. Twenty-five studies describing 45 cases have been reported. Prostate melanoma is characterized by an insidious onset and poor prognosis. The prognosis and treatment vary according to primary or secondary melanoma.

CASE SUMMARY

A 75-year-old man attended the hospital due to low back pain of 2 mo duration. He denied a history of trauma or abnormal urinary symptoms. Digital rectal examination showed indentation in the left lobe of the prostate, 1 cm in diameter. His prostate-specific antigen was 5.6 ng/mL and 18F-fluorodeoxyglucose positron emission tomography computed tomography (18F-FDG-PET/CT) showed focal glucose metabolism in the left lobe. Imaging showed bone metastases to T12 and bilateral ribs. Transperineal prostate biopsy was done and three tissue specimens on the left side showed prostate adenocarcinoma (Gleason score 3 + 3 = 6), but the specimen on the right side showed malignant melanoma. The patient underwent T12 tumor resection and pathology findings indicated metastatic malignant melanoma. The patient underwent gastroscopy and colonoscopy, and gastroscopy revealed multiple mucosal black spots in the gastric body and fundus. The patient was diagnosed with secondary malignant prostate melanoma and primary gastric disease.

CONCLUSION

Diagnosis of primary prostate melanoma requires caution and 18F-FDG-PET/CT may result in false-negative detection of melanoma.

Solitary fibrous tumors in prostate: a case report with review of the literature

BACKGROUND

Solitary fibrous tumor (SFT) is a relatively rare type of mesenchymal neoplasm that occurs most frequently in the pleura. However, SFT originating from the prostate is particularly uncommon and only approximately 39 cases were reported before. Herein, we reported a rare case of a patient diagnosed with prostate SFT and presented a literature review.Case presentation: A 50-year-old Asian with irritative urinary symptoms was admitted to our hospital and almost all the evidence indicated that benign prostate hyperplasia (BPH) caused his symptoms. Therefore, transurethral resection of the prostate (TURP) was performed, but histopathological and Immunohistochemical (IHC) assessments showed that spindle cells arranged disorderly in the TURP specimen with a cluster of differentiation 34 (CD34), B-cell lymphoma-2 (Bcl-2), and signal transducer and activator of transcription 6 (STAT6) highly expressed and SFT was diagnosed. Finally, the patient underwent a radical prostatectomy and there was no disease progression observed thereafter.

CONCLUSIONS

Prostate SFT is extremely rare, and to our knowledge, this is the first case of prostate SFT that is difficult to differentiate from small volume BPH. IHC examinations are of great diagnostic value. Radical resection of the tumor appears to be the most effective method at present and continuous follow-up is highly recommended.

Mesenchymal Neoplasms of the Prostate and Seminal Vesicles: Spectrum of Disease with Radiologic-Pathologic Correlation

There is a wide spectrum of benign and malignant mesenchymal neoplasms of the prostate, which account for less than 1% of all prostatic tumors. These include distinctive tumors that arise from the specialized prostatic stroma and site-agnostic neoplasms such as smooth muscle tumors, fibrous or myofibroblastic neoplasms, neurogenic tumors, vascular tumors, and a plethora of sarcomas. Select tumors show classic sites of origin within the prostate. While stromal tumors of uncertain malignant potential (STUMPs) commonly involve the peripheral zone at the prostate base, leiomyomas typically originate from the central prostate toward the apex. Some "prostatic" neoplasms such as gastrointestinal stromal tumors, solitary fibrous tumor (SFT), paragangliomas, and neurogenic tumors arise primarily from periprostatic soft tissues. Most mesenchymal tumors of the prostate and seminal vesicles manifest as large tumors that cause nonspecific symptoms; prostate-specific antigen level is not typically elevated. Diverse mesenchymal neoplasms demonstrate characteristic histopathologic and immunocytochemical features and variable cross-sectional imaging findings. While leiomyoma and SFT typically display low signal intensity on T2-weighted images, synovial sarcomas commonly show hemorrhage. Diagnosis is difficult because of the rarity and lack of awareness of the tumors and the significant overlap in histopathologic features. Select tumors show characteristic genetic abnormalities that allow the diagnosis to be established. For example, more than 90% of SFTs are characterized by a unique NAB2-STAT6 gene fusion, and more than 95% of synovial sarcomas are associated with a distinctive SYT-SSX chimeric transcript. Accurate diagnosis is imperative for optimal management owing to markedly different tumor biology as well as attendant therapeutic and prognostic implications. While STUMPs commonly recur, sarcomas typically charter an aggressive course with poor prognosis. Online supplemental material is available for this article. ^©RSNA, 2022.

Recurrent malignant solitary fibrous tumor of the scalp: a case report and literature review

Solitary fibrous tumor (SFT) is a rare type of mesenchymal neoplasm that first was discovered in the pleura but can also affect the peritoneum, lungs, mediastinum, and skin. Cutaneous malignant SFT is an extremely rare tumor that resembles dermatofibrosacoma protuberance (DFSP) histologically and immunohistochemically. Herein, we describe a case of malignant SFT that presented as a recurrent mass on the scalp. The first lesion was totally excised one year before recurrence and was diagnosed as a DFSP based on the histopathology and cluster of differentiation 34 immunostaining positivity. Re-examination of the previously examined specimen was considered. Activator of transcription 6 positivity was also detected in the tissue, confirming the diagnosis of a recurrent malignant SFT rather than DFSP. There was no evidence of recurrence, locoregional, or distant metastases at six months after lesion removal with a safety margin.

Detection limits of significant prostate cancer using multiparametric MR and digital rectal examination in men with low serum PSA: Up-date of the Italian Society of Integrated Diagnostic in Urology

Reasons why significant prostate cancer is still missed in early stage were investigated at the 22nd National SIEUN (Italian Society of integrated diagnostic in Urology, Andrology, Nephrology) congress took place from 30th November to 1st December 2020, in virtual modality. Even if multiparametric magnetic resonance (MR) has been introduced in the clinical practice several, limitations are emerging in patient with regular digital rectal examination (DRE) and serum prostate specific antigen (PSA) levels approaching the normal limits. The present paper summarizes highlights observed in those cases where significant prostate cancer may be missed by PSA or imaging and DRE. The issue of multidisciplinary interest had been subdivided and deepened under four main topics: biochemical, clinical, pathological and radiological point of view with a focus on PI-RADS 3 lesions.

Imaging of non-epithelial neoplasms of the prostate

The purpose of this article is to review the spectrum of rare non-epithelial tumors of the prostate. This focused article will help the readers to understand the imaging findings of such rare entities attributed to their clinicopathological features. Radiologists must be familiar with the spectrum of non-epithelial tumors of the prostate, which helps to suggest alternate diagnosis other than adenocarcinoma, when imaging features are atypical. This is important because these tumors have different management approaches and prognoses when compared to adenocarcinoma of the prostate.

The FGF/FGFR system in the physiopathology of the prostate gland

Fibroblast growth factors (FGFs) are a family of proteins possessing paracrine, autocrine, or endocrine functions in a variety of biological processes, including embryonic development, angiogenesis, tissue homeostasis, wound repair, and cancer. Canonical FGFs bind and activate tyrosine kinase FGF receptors (FGFRs), triggering intracellular signaling cascades that mediate their biological activity. Experimental evidence indicates that FGFs play a complex role in the physiopathology of the prostate gland that ranges from essential functions during embryonic development to modulation of neoplastic transformation. The use of ligand- and receptor-deleted mouse models has highlighted the requirement for FGF signaling in the normal development of the prostate gland. In adult prostate, the maintenance of a functional FGF/FGFR signaling axis is critical for organ homeostasis and function, as its disruption leads to prostate hyperplasia and may contribute to cancer progression and metastatic dissemination. Dissection of the molecular landscape modulated by the FGF family will facilitate ongoing translational efforts directed toward prostate cancer therapy.

Melanocytic lesions of the prostate

Background

Benign melanocytic lesions of the prostate are rare and classified as blue nevus or melanosis. Both lesions have about 30 cases each reported in English literature.

Case presentation

We report here two illustrative cases, both incidental findings: a blue nevus at transurethral resection specimen and melanosis in needle biopsy. The second case was of a patient who underwent prostate biopsy due to a PI-RADS 5 finding in multiparametric MRI. Although no cancer was detected, findings suggestive of nodular hyperplasia and diagnostic of melanosis were observed.

Conclusion

Benign melanocytic lesions of the prostate are rare incidental findings with no clinical or prognostic relevance. Additional reports are warranted to evaluate whether such lesions may be associated with suspicious findings in imaging exams.

Demographics, stage distribution, and relative roles of surgery and radiotherapy on survival of persons with primary prostate sarcomas

Background

Primary prostate sarcomas (PPS) are rare. Outcomes for this cancer have not been well characterized.

Materials and Methods

Subjects with a PPS diagnosed between 1973 and 2014 were identified in the SEER database. Subjects were stratified by disease stage and types of therapies received. Disease‐specific survival (DSS) and Overall survival (OS) was estimated by Kaplan‐Meier analysis and cohorts were compared with a univariate and multivariable Cox regression.

Results

The incidence of PPS among all prostate cancer diagnoses was 0.02%. Subjects younger than age 26 years at diagnosis represented 29% of cases, and 32% of primary prostate sarcomas were rhabdomyosarcoma histology.

Rhabdomyosarcoma Histologies

The median age at diagnosis was 9 years. Between age 0‐25 years rhabdomyosarcoma accounted for 96.4% of primary prostate sarcoma diagnoses, after age 25 rhabdomyosarcoma represented 15% of new diagnoses. The 10‐year DSS and OS for rhabdomyosarcoma was 47% and 44%.

Non‐Rhabdomyosarcoma Histologies

The median age at diagnosis was 71 years. The most common diagnoses were leiomyosarcoma (33%) and carcinosarcoma (28%). Localized, regional, or distant disease occurred in 40%, 34%, and 26% of cases. The 10‐year DSS and OS were 26% and 14%. In locally advanced cases, RT added to surgery trended toward improved DSS (P = 0.10).

Conclusions

Disease‐specific survival and OS for non‐rhabdomyosarcoma histologies appear inferior to those of rhabdomyosarcoma. The addition of RT to surgical resection may improve DSS in locally advanced non‐rhabdomyosarcoma. This is the largest report of the incidence, stage distribution, and survival for this extremely rare urologic malignancy providing valuable prognostic information.

Detection and Treatment of Primary Prostatic Melanoma

OBJECTIVE

To describe a case of primary melanoma of the prostate gland, then review the published literature of similar cases.

METHODS

Presentation of the clinical course of a 42-year-old man diagnosed with primary melanoma of the prostate after presenting with gross hematuria. Review of published literature.

RESULTS

Primary melanoma of the genitourinary tract is a very rare disease, representing less than 1% of all melanomas in men. Only 6 cases of primary melanomas have been previously reported in the English literature.

CONCLUSION

The current report emphasizes the importance of a multidisciplinary approach and adherence to treatment principles in cutaneous melanoma. With complete surgical extirpation (including extended pelvic lymphadenectomy as needed), close surveillance using 18F-FDG PET/CT, and aggressive systemic treatment in patients with good performance status, cure can be achieved.

A rare case of malignant solitary fibrous tumor in prostate with review of the literature

Background

Solitary fibrous tumor is an uncommon soft tissue neoplasm with intermediate biological behavior, which rarely metastasizes. Malignant solitary fibrous tumor, although not clearly defined, is rarely described in the prostate. The present case is characterized by some peculiarities if compared with previously reported cases of prostatic malignant solitary fibrous tumor. Firstly, it does not show a homogeneous morphology: part of the neoplasm (about 50%) showed the features of a conventional solitary fibrous tumor, while the remaining part showed the features of a malignant solitary fibrous tumor. In addition, the case is the first malignant solitary fibrous tumor reaching a huge diameter of 20 cm and replacing all prostatic parenchyma. Interestingly, normal prostatic parenchyma was observed on left-lobe trans-rectal needle-core biopsies, but was totally absent in surgical specimen. Since radical prostatectomy was carried out about 4 months after the biopsies, such discordant data may suggest exceedingly rapid growth of the neoplasm.

Case presentation

We report a case of a 62-year-old male, presented at medical observation for urinary retention, constipation and an enlarged prostate gland. A trans-rectal prostatic biopsy showed a low-grade spindle cell neoplasm. Histopathological examination of the prostatectomy specimen showed patternless architecture with hypocellular and hypercellular areas and hemangiopericytoma-like vessels. In some fields the neoplasm was characterized by a high mitotic index and evident cellular atypia. Immunohistochemically, neoplastic cells were positive for CD34, bcl2, CD99, STAT6 and partially for PgR. The neoplasm was diagnosed as a malignant solitary fibrous tumor.

Conclusions

The differential diagnosis of spindle cells tumors arising in the prostrate is broad and includes lesions of epithelial and mesenchymal origin, primary prostatic lesions such as stromal tumors of uncertain malignant potential and stromal sarcoma, as well as anatomically ubiquitous soft tissue neoplasms. Solitary fibrous tumors should be considered in cases of prostatic tumors with a spindled morphology, but malignancy in such tumors is extremely rare in the prostate. A review of literature showed only four additional cases. Because of the unpredictable biological behavior and the possibility of recurrence, a long-term clinical and instrumental follow-up is recommended.

Malignant Peripheral Nerve Sheath Tumor of Prostate: A Rare Case Report and Literature Review

A mid-aged male presented with progressive lower urinary tract symptoms (LUTS) for years. Huge prostate with low serum prostate-specific antigen (PSA) level was detected. The specimen from transurethral resection revealed surprising pathology finding as malignant peripheral nerve sheath tumor (MPNST). Considering its huge size (more than 300 gm) and location, we prescribed neoadjuvant chemotherapy firstly. The tumor became regressive and then radical surgical resection was achieved. Adjuvant multimodality treatment including concurrent chemoradiotherapy (CCRT) and target therapy was given. However, he expired about one year later. MPNST originating from prostate is very rare and seldom reported before. We here present this extremely rare disease and share our treatment experience.

Prostatic melanosis

Prostatic melanosis is a very rare, benign lesion characterized by the presence of melanin in the epithelium of the prostate gland and stromal dendritic cells, requiring no additional treatment. It constitutes the melanocytic lesions of the prostate together with blue nevus and malignant melanoma. We present a case with prostatic melanosis because it is rarely seen and its distinction from malignant melanoma is clinicopathologically very important.

Cellular angiofibroma of the prostate: a rare tumor in an unusual location

We report the unusual occurrence of a cellular angiofibroma in prostatic tissue. In this case, a 84-year-old man presented in the emergency room with urinary retention. Ultrasound revealed an enlarged prostate, which was suggestive for benign prostatic hyperplasia. The patient was treated with a Millin retropubic prostatectomy. Macroscopically the prostate contained multiple circumscribed nodules. Microscopic examination of the tumor showed the appearance of cellular angiofibroma, consisting of bland spindle cells and prominent, hyalinized vessels. The diagnosis was supported by FISH, which revealed monoallelic loss of RB1/13q14 region, as seen in spindle cell lipoma, (extra-) mammary myofibroblastoma, and cellular angiofibroma. Cellular angiofibromas are rare, benign soft tissue tumours and were never reported in the prostatic gland.

Malignant nonepithelial prostate tumors: FDG PET/CT findings with MRI and CT correlation

PURPOSE

The aim of this study was to evaluate F-FDG PET/CT findings of malignant nonepithelial prostate tumors and their correlation with MRI and CT images.

PATIENTS AND METHODS

FDG PET/CT findings were reviewed in 12 patients with malignant nonepithelial prostate tumor confirmed by pathology. The location, size, SUVmax, pathologic findings, and available MRI and CT images of the tumors were reviewed.

RESULTS

Of the 12 patients (mean age, 41 years; age range, 19-66 years), 9 had normal prostate-specific antigen levels. The mean size of the tumors was 7.1 cm in diameter ranging from 4.6 to 10.5 cm. All the tumors showed increased metabolic activity with mean SUVmax of 17.5 ranging from 3.6 to 46.8. The high-grade malignant tumors tended to show higher FDG uptake, whereas the intermediate-grade and low-grade malignant ones tended to show lower FDG uptake. Seven tumors had local invasion or distant metastases. Lung was the most common metastatic site. On MRI, the tumors showed well-circumscribed or ill-circumscribed margins with inhomogeneous enhancement. On CT, the tumors showed hypodensity with slight to moderate enhancement.

CONCLUSIONS

The malignant nonepithelial prostate tumors tended to have large sizes at presentation, have high FDG uptake, and affect a younger population with normal prostate-specific antigen levels. FDG PET/CT may be useful for the assessment of tumor grade and for detecting the distant metastases, whereas the MRI or enhanced CT may be more helpful for describing the relationship between the tumor and adjacent structures.